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Drilled And Slotted Rotors: The Ultimate Guide (2021)

March 25, 2021

Want to learn about drilled and slotted rotors to determine if they’re a good fit for your needs?

Drilled and slotted rotors are brake rotors with holes and slots in them. 

They’re designed to evacuate the moisture and brake dust generated during braking, facilitate the cooling of your brake disc, and increase your contact friction for superior brake performance.

In this article, we’ll cover what slotted and drilled rotors are and why you might consider them for your vehicle. Then, we’ll look at some of their limitations and how to spot failing rotors. Finally, we’ll look at the best way to keep your slotted and drilled rotors in check.

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Let’s get started.

What Is A Drilled And Slotted Rotor?

A drilled and slotted rotor is a type of brake rotor with a series of drilled holes in them and curved grooves machined across its surface. 

What is a brake rotor?

A brake rotor (a.k.a. a brake disc) is a crucial component of your disc brake system. It provides a point of contact for the brake pad when you press down on the brake pedal.

Essentially, when you hit the brakes, brake calipers near the wheels compress your brake pads (which could be ceramic pads or metallic brake pads) against your brake disc or rotor to generate friction.

This friction force helps slow down the car and bring it to a halt.

What are the different kinds of rotors?

Besides the slotted and drilled rotors, you also have the:

Drilled and slotted brake rotors are a popular choice for high-performance and heavy-duty vehicles like tow trucks, motorsport cars, and more. They offer improved stopping power and help you combat brake fade.

Note: Brake fade is the gradual decrease in stopping power of your braking system due to prolonged use.

Why Use Drilled And Slotted Brake Rotors

Here are some reasons why you should consider using slotted and drilled brake rotors for your car:

1. Enhanced Brake Grip

Slotted and drilled rotors offer enhanced brake grip for more efficient brake performance. 

When you’re braking, the kinetic energy of your vehicle is converted into heat because of all the friction in your brakes. As a result, repeated braking leads to higher temperature rises.

At elevated temperatures, the resins in your brake pad material can burn up to produce gases that ultimately compromise your braking performance. Fortunately, the disc brake rotors’ drilled holes can quickly expel these offset gases to restore braking grip rapidly.

2. Heavy-Duty Brake Support

Heavy-duty and high-performance vehicles like trucks require extra braking support.

Why?

As they’re very heavy, they usually need more stopping power to slow down.

Drilled and slotted rotors are excellent at delivering that powerful yet smooth braking performance to bring your heavy-duty vehicle to a stop.

3. Wet Climate Suitability

When you’re driving in wet climates, the profile of your braking system changes.

The presence of moisture in between your brake pad surface and brake rotor can reduce the amount of friction force your braking system generates. And this leads to lower stopping power for your cars.

The drilled holes in your disc brake rotor allow the moisture and brake dust to escape. This keeps your brake rotors dry, helping you achieve consistent braking performance even in wet weather conditions.

4. Slows Down Brake Pad Glazing

If you’re going down a hill or are stuck in traffic, you’re likely to apply brakes more frequently.

Doing so can increase the temperature of your brake system, and this causes your brake pad surface to smoothen and harden (known as glazing). Over time, the pad surface starts to mirror the brake rotor, and the pad material becomes incapable of generating sufficient friction.

Fortunately, in drilled and slotted brake rotors, the grooves on your rotor chip off the pad material to slow down glazing.

What Are The Limitations Of Using Slotted And Drilled Rotors?

Although a drilled and slotted rotor offers many advantages over a plain rotor (smooth rotor), it does have some downsides. Here are some limitations of slotted and drilled brake rotors that you need to watch out for:

1. Premature Brake Rotor Wear

Sometimes, your drilled and slotted discs tend to wear out prematurely.

It usually happens because the same areas of your brake rotors are in contact when you apply the brakes, resulting in uneven wearing.

This is more common if you’re using drilled and slotted discs in a high-performance vehicle. The high temperature and repeated stresses that these rotors encounter could cause them to develop cracks and wear down over time.

2. Short Rotor Lifespan

Generally, drilled and slotted discs tend to have a shorter lifespan compared to blank rotors.

With that being said, if you encounter harsh driving conditions regularly and are likely to engage in heavy braking, your drilled and slotted brake rotors will wear out even quicker and might need replacing as often as your brake pad set.

On average, you can expect to replace your slotted and drilled rotors between 25,000 to 35,000 miles.

3. Steering Wheel Vibrations

Your drilled and slotted rotor tends to wear out in concentric circles.

When that happens, your hole patterns get disrupted, and this can result in vibrations on your steering wheel.

4. Can’t Resurface Rotors

A significant disadvantage with drilled and slotted rotors is that you can’t resurface it, unlike a smooth rotor (plain rotor).

If your drilled and slotted brake rotors are distorted or damaged, they can significantly affect your brake performance, and you’ll need to replace your stock rotor.

And replacing a stock rotor is usually more expensive than resurfacing one.

What Are The Symptoms Of Failing Drilled And Slotted Rotors?

A drilled and slotted brake rotor affects how much braking power your car generates, so driving around with a defective drilled and slotted rotor can be a significant safety hazard.

If you notice any of the symptoms below, consider getting your drilled and slotted rotor inspected and replaced by a mechanic:

1. Squealing Noise When Applying Brakes

If you’re hearing high-pitched squealing or squeaking noises while applying the brakes, chances are that your drilled and slotted rotor is badly worn out or warping.

And if you’ve got extensively warped rotors, you’ll probably hear scraping sounds.

When this happens, take your car to an auto repair shop, or have a mechanic come over and inspect your rotor surface and other brake parts (such as the brake pads, brake calipers, brake fluid lines, and more) to identify the underlying issues.

2. Excessive Brake Vibration

If you start to feel irregular vibrations on your brake pedal or through the vehicle chassis, it could be because of damaged slotted and drilled brake rotors.

Why?

Warping rotors tend to generate a pulsating effect that ripples through your car.

3. Grooves On Brake Rotor

This isn’t something you can readily notice. However, if you do manage to see unusual grooves or scoring marks on your rotor surface, your slotted and drilled rotors might undergo imminent failure.

These marks, which develop over time from repeated contacts with your brake pad, can significantly weaken your brake system and can cause brake pulsations that you can feel on the brake pedal.

In such a scenario, request a brake system inspection.

Just remember that when hiring a mechanic, ensure that they:

Luckily, there’s an easy way to find mechanics who match all of these criteria and more:

The Best Way To Keep Your Brake Rotors In Check

Driving with a defective drilled and slotted rotor can compromise your road safety. 

That’s why it may not be practical to drive your car to an auto repair shop.

The most convenient way to get your brake rotors inspected and replaced is to have a mobile mechanic come over. And if you’re looking for a mobile car repair solution, look no further than RepairSmith!

RepairSmith is a convenient mobile car repair and maintenance solution that offers you these benefits:

How Much Does A Brake Rotor Replacement Cost?

The cost of replacing your brake rotor usually depends on the vehicle model and make. With that being said, you can expect to pay anywhere between $230 and $500 for a brake rotor replacement.

For a more accurate estimate, fill this online form by entering the year, make, model, and engine details. 

Keep Your Rotors In Check

Slotted and drilled discs (rotors) are an effective way to enhance brake grip, combat brake fade, and help you drive in wet weather conditions. 

However, because of its potentially shorter life and inability to be resurfaced, you’ll need to ensure that your performance rotor stays in check.

If you notice any symptoms that indicate your brake rotor is damaged, consider having your drilled and slotted rotor inspected and replaced ASAP.

And if you want to get your brake rotor repairs done right in your driveway, the easiest way to do so is to get in touch with RepairSmith.